Beard, Jennifer, author
Routledge, 2007
Buku Teks
Flint, Colin, author
Pearson/Prentice Hall, 2007
Buku Teks
Flint, Colin, author
Taylor and Francis Group, 2018
Buku Teks
Flind, Colin, author
Routledge, 2018
Buku Teks
Taylor, Peter J., author
Longman, 1995
Buku Teks